libelf: use separate make and make install steps

Closes Homebrew/homebrew#11943.
c.f. Homebrew/homebrew#11982.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/libelf.rb

@@ -1,12 +1,17 @@
 require 'formula'
 
 class Libelf < Formula
-  url 'http://www.mr511.de/software/libelf-0.8.13.tar.gz'
   homepage 'http://www.mr511.de/software/'
+  url 'http://www.mr511.de/software/libelf-0.8.13.tar.gz'
   md5 '4136d7b4c04df68b686570afa26988ac'
 
   def install
-    system "./configure", "--disable-debug", "--disable-dependency-tracking", "--prefix=#{prefix}"
+    system "./configure", "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--prefix=#{prefix}"
+    # Use separate steps; there is some kind of (transient)
+    # race in the Makefile.
+    system "make"
     system "make install"
   end
 end